4 papers related to Robin's criterion on RH :

Robin_1984.pdf : Guy Robin, Grandes valeurs de la fonction somme des diviseurs et hypothese de Riemann (RH)
Nicolas_83_Planat.pdf : On Nicolas criterion for the Riemann hypothesis (RH)
Nicolas_petitsphi83.pdf : Jean-Louis Nicolas, Petites valeurs de la fonction Phi d'Euler (totient)
Nicolas_1988.pdf : On highly composite numbers


see also : math.stackexchange.com/questions/93803/where-can-i-find-the-paper-by-guy-robin
and Nicolas's publications and the work of Lagarias : An Elementary Problem Equivalent to the Riemann Hypothesis (RH), Jeffrey C. Lagarias